Power used to be associated with having the last word. The goal of most discussions was to conclude on one's own terms, and usually that meant planting the final period. No more questions will be entertained, the last word indicated; no objections brooked. Seinfeld's George Costanza was a master of this principle. His strategy in meetings was to say something smart, declare "That's it for me!" and immediately exit the room.

E-mail has sent those dynamics tumbling tail over teacups. A physical conversation ends when one participant indicates in words or body language that it's over. An e-mail conversation, by contrast, ends when one participant stops responding. "As far as I'm concerned we're done here," the nonresponder's silence says. If the exchange has been protracted, the implication may be construed as less polite: "Enough of this. I'm moving on to more important things." Meanwhile, the party who sent the last note checks his in box for a reply. Not receiving one, he feels at least nominally rejected, although rationally he knows that rejection is probably not implied.

While few employees would simply walk out on a discussion with the CEO, not replying to the boss's e-mail (so long as it doesn't include a direct question) is generally considered acceptable. If you're the kind of boss whose in box resembles Fibber McGee's closet, you may actually prefer receiving no response. Still, from a power perspective, you want to be the one who calls it quits. So you play e-mail chicken.

The goal of e-mail chicken is to cease communicating before the other player does. (A grand-master variant involves passing shorter and shorter messages to the point where you and your correspondent are exchanging blank screens.) The trick is to pinpoint the exact moment when all that needs saying has been said and any additional comment can be interpreted as over-eagerness, cluelessness, or the product of excessive leisure time. That moment is hard to spot, because e-mail is like lobster: The best stuff's often in the tail.

Fortunately, there are ways to terminate a game of e-mail chicken that won't leave you wind-twisting:

Respond tersely. Standing alone, "fine," "good," and "okay" are last words in the old-school sense. The employee knows she's not expected to reply.

Make an explicit call to action. Polite but firm requests ("Please call Algernon as soon as possible"; "Kindly get that report to Klingburg by this afternoon") close the exchange on your terms. The employee knows he's not expected to reply because he's supposed to be charging around looking for the Klingburg file.

Talk to the other party in person. One neat thing about human contact is that you can end conversations in a draw. "So we have a plan?" "That we do." "Great." "Good." "We'll catch up later." "Okey-doke."

If you find yourself playing chicken with vendors, partners, or customers, the strategy becomes more nuanced and the power stakes higher. With customers, for example, it is always wise to blink first. Your final message: "Please let me know if there is anything else we can do for you."

Leigh Buchanan is an Inc. editor-at-large. She can be reached at lbuchanan@inc.com.